Quantum Electronics and Laser Science Conference
Reliability of the beamsplitter based Bell-state measurement
Yoon-Ho Kim, Warren P. Grice
Abstract
A linear 50/50 beamsplitter, together with a coincidence measurement, has been widely used in quantum optical experiments, such as teleportation, dense coding, etc., for interferometrically distinguishing, measuring, or projecting onto one of the four two-photon polarization Bell-states |/spl Psi//sup (-)/>. In this paper, we demonstrate that the coincidence measurement at the output of a beamsplitter cannot be used as an absolute identifier of the input state |/spl Psi//sup (-)/> nor as an indication that the input photons have projected to the |/spl Psi//sup (-)/> state.